First- and Second-season Effect on Douglas-fir Cone Initiation from a Single Shade Period

1973 ◽  
Vol 3 (4) ◽  
pp. 528-534 ◽  
Author(s):  
Roy R. Silen
Keyword(s):  
Treatment Effects ◽  
Douglas Fir ◽  
Seed Cone ◽  
Pollen Cone

Shade (12–23% sunlight) applied for monthly periods between February and September to individual branches in upper whorls of 40-year-old Pseudotsugamenziesii caused increased pollen-cone (♂) and decreased seed-cone (♀) buds counted in autumn of the year of treatment. A consistent decreased count in both bud types the following year indicated treatment effects were carried over, raising the question as to when inducive events actually take place in Douglas-fir.

Hormonal enhancement of cone production in Douglas-fir grafts and seedlings

1979 ◽  
Vol 9 (2) ◽  
pp. 193-200 ◽  
Author(s):  
George S. Puritch ◽  
Eleanor E. McMullan ◽  
Michael D. Meagher ◽  
Clarence S. Simmons
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Douglas Fir ◽  
Naphthaleneacetic Acid ◽  
Viable Seed ◽  
Seed Orchards ◽  
Cone Production ◽  
Seed Cone ◽  
Pollen Cone ◽  
Production Response

Gibberellic acid (GA) and naphthaleneacetic acid (NAA) were applied alone and in combination to both girdled and nongirdled branches of Douglas-fir in four seed orchards (two containing seedlings and two containing grafts). GA significantly increased seed-cone buds and cones and caused a nonsignificant increase in pollen-cone buds. Cone production was not significantly affected by girdling or the application of NAA. Trees treated with the combination of GA + NAA responded similarly to those treated with GA alone. Cone production response to GA varied according to the orchard locations, with better response in the normally more productive orchards. The percentage of trees flowering was increased by GA. Hormone treatments had no effect on seeds per cone but they significantly reduced filled seed per cone. Owing to increased cone number, however, the GA treatments greatly increased the yield of viable seed. NAA increased the percentage of seed germinating and the rate of seed germination, while GA had no effect.

Cost of reproduction in Douglas-fir

1992 ◽  
Vol 70 (7) ◽  
pp. 1429-1432 ◽  
Author(s):  
Yousry A. El-Kassaby ◽  
Hugh J. Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Annual Ring ◽  
Ring Width ◽  
Energy Allocation ◽  
Douglas Fir ◽  
Environmental Correlations ◽  
Annual Ring Width ◽  
Trade Off ◽  
Cone Production ◽  
Seed Cone

The balance between allocating energy resources to reproduction or growth has considerable theoretical interest. Conflicting ecological requirements and evolutionary pressures often necessitate a trade-off in energy allocation. We obtained measurements on seed-cone production and annual ring width of 365 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from 29 open-pollinated families for 8 years. Phenotypic, genetic, and environmental correlations were computed for seed-cone production and ring width for each year. Five of the eight environmental correlations were negative (range −0.077 to −0.305), reflecting the reality of the trade-off in physiological terms. Six of the eight genetic correlations were negative (range −0.199 to −0.776), indicating that a trade-off exists at the genetic level between energy allocation to reproduction and to somatic growth. These findings agree with the current theory of life-history evolution. Key words: Pseudotsuga menziesii, cone production, annual ring width, genetic correlation.

Clonal variation in pollen-related characteristics of Douglas-fir

1982 ◽  
Vol 12 (2) ◽  
pp. 403-408 ◽  
Author(s):  
W. T. Adams
Keyword(s):  
Genetic Variation ◽  
Pollen Grains ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Clonal Variation ◽  
Pollen Production ◽  
The Mean ◽  
Pollen Cone ◽  
Grain Diameter

The mean number of pollen grains produced per pollen cone (P) ranged from 37 310 to 62 960 ([Formula: see text], SE = 1584) among eight seed-orchard clones of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and correlated significantly (r = 0.87, p < 0.05) with the mean number of microsporophylls per cone but not significantly with pollen cone length. The number of pollen grains per milligram (G) also differed among clones (range 2323–3112; [Formula: see text], SE = 32) and correlated significantly and negatively (r = −0.86) with grain diameter. Although this study provides evidence for genetic variation in both P and G, the differences were relatively small. Adjusting pollen-cone counts for P would add little, if any, precision to estimates of pollen production in seed-orchard clones. If balanced clonal representation in pollen mixes is desired, equal weights of pollen would probably suffice for most breeding applications.

The pollination mechanism and development after bud burst of cones of Larix laricina

1991 ◽  
Vol 69 (6) ◽  
pp. 1179-1187 ◽  
Author(s):  
G. R. Powell ◽  
Kathleen J. Tosh
Keyword(s):  
Key Words ◽  
Seed Size ◽  
Larix Laricina ◽  
Bud Burst ◽  
Scale Growth ◽  
Pollination Mechanism ◽  
Seed Cone ◽  
Cone Development ◽  
Micropylar Canal ◽  
Pollen Cone

Pollen-cone and seed-cone development, from bud burst to maturity, was investigated on Larix laricina (Du Roi) K. Koch in three young plantations. The pollination mechanism was emphasized. Pollen cones grew rapidly to shed pollen, shrivelled, and remained on the trees for a year or more. Pollen was directed to the ovular regions by the bracts of the seed cones. Pollen adhered among papillae on the larger of two integument extensions. Degeneration of the centre of the papillate integument tip caused a collapse that drew pollen in as the papillate rim grew inward. This ingrowth was joined by that of the smaller integument extension, resulting in a sealed tubular structure that enclosed a dry micropylar canal. Pollen was held by the ingrown plug of degenerated tissue as the nucellus tip expanded into the base of the canal. As this occurred, the ovules, with or without pollination, grew to ultimate seed size, and the initially small ovuliferous scales overgrew the bracts. First bract, then ovuliferous-scale growth was associated with a double-sigmoid form of cone elongation. In mature cones the bracts decreased and the ovuliferous scales (except near the tip) increased in size acropetally. Key words: bract, integument, ovuliferous scale, pollen cone, seed cone, tamarack or eastern larch.

Promotion of flowering in western hemlock by gibberellin A4/7 applied at different stages of bud and shoot development

1989 ◽  
Vol 19 (8) ◽  
pp. 1051-1058 ◽  
Author(s):  
John N. Owens ◽  
Anna M. Colangeli
Keyword(s):  
Effective Treatment ◽  
Shoot Elongation ◽  
Shoot Development ◽  
Western Hemlock ◽  
Bud Burst ◽  
Cone Production ◽  
Seed Cone ◽  
Pollen Cone ◽  
Vegetative Bud

Cone buds were induced on container-grown and field-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) clones during a 3-year period to study the effects of time and duration of gibberellin A4/7 treatment on cone induction, sexuality of cones, and to relate these results to bud and shoot development. The most effective treatment times preceded anatomical differentiation. The most abundant pollen cones and seed cones were produced when trees were sprayed with gibberellin A4/7 before vegetative bud burst and early shoot elongation. Two to three weekly gibberellin A4/7 applications starting at preswollen and swollen-bud stages were adequate for pollen-cone production. Pollen-cone production decreased when the applications were started at vegetative bud burst or during early shoot elongation. A minimum of three weekly applications were required for seed-cone production, and applications were equally effective when started at preswollen, swollen, and vegetative bud burst stages. Seed-cone production decreased when three weekly applications were started during early shoot elongation; however, this was overcome by increasing the number of applications.

Bud development in mountain hemlock (Tsuga mertensiana). II. Cone-bud differentiation and predormancy development

1984 ◽  
Vol 62 (3) ◽  
pp. 484-494 ◽  
Author(s):  
John N. Owens
Keyword(s):  
Shoot Elongation ◽  
Bud Development ◽  
Seed Cone ◽  
Cone Apex ◽  
Tsuga Mertensiana ◽  
Lateral Branches ◽  
Mother Cells ◽  
Pollen Cone ◽  
Bud Initiation ◽  
Vegetative Bud

Seed cones of Tsuga mertensiana (Bong) Carr. occur terminally on distal lateral branches and form from the differentiation of a terminal, previously vegetative apex, into a seed-cone apex. Pollen cones commonly occur on lateral branches and form from the differentiation of an undetermined axillary apex about 6 weeks after axillary bud initiation. Pollen cones also occasionally occur terminally. All cone buds began differentiation in late July after bud-scale initiation was complete and at about the end of lateral shoot elongation. Seed-cone buds initiated bracts and ovuliferous scales, but not ovules, before they became dormant at the end of October. Pollen-cone buds initiated all microsporophylls by early September. Microsporangia containing microspore mother cells differentiated before pollen-cone buds became dormant in mid-October. The time of cone-bud differentiation is related to vegetative bud and shoot development. The time and method of cone-bud differentiation is discussed in relation to T. heterophylla and other conifers having similar bud development.

Cone initiation and development before dormancy in yellow cedar (Chamaecyparis nootkatensis)

1974 ◽  
Vol 52 (9) ◽  
pp. 2075-2084 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder
Keyword(s):  
Mitotic Activity ◽  
Lateral Branch ◽  
Leaf Primordia ◽  
Day Length ◽  
Chamaecyparis Nootkatensis ◽  
Seed Cone ◽  
Cone Development ◽  
Cone Apex ◽  
Lateral Branches ◽  
Pollen Cone

Vegetative shoots initiate leaves and lateral branches continuously from mid-April until the end of September. No buds with bud scales are formed and the vegetative apex is enclosed by leaf primordia at various stages of development. Pollen cones are initiated on proximal vegetative shoots during a 3-week period from mid-June to early in July. Transition to a pollen-cone apex is marked by an increase in mitotic activity in the apex and by the formation of a lateral branch in the axil of one of the last-formed leaf primordia, causing the apex to appear to branch dichotomously. The lateral branch remains at the base of the pollen cone and may resume growth the next year after the pollen cone is shed. Pollen-cone development continues until the end of September. Meiosis occurs during the last 2 weeks of August, and pollen develops during September. Seed cones are initiated on newly formed, distal axillary vegetative shoots during a 3-week period from late June to mid-July. Transition to a seed-cone apex is marked by an increase in mitotic activity followed by bract-scale initiation. Usually three ovules are initiated in the axil of each bract scale. Seed-cone development is complete by early September and the seed cones become dormant. The pattern of reproduction in yellow cedar is compared to other conifers and the possible relationships are discussed between time of cone initiation, sexuality of cones, and day length.

Gibberellin A4/7 enhanced flowering in Pinuscaribaea var. hondurensis

1991 ◽  
Vol 21 (6) ◽  
pp. 788-793 ◽  
Author(s):  
Derek L. S. Harrison ◽  
Mike U. Slee
Keyword(s):  
Single Treatment ◽  
Bud Development ◽  
Cone Production ◽  
Seed Cone ◽  
Pollen Cone ◽  
Sexually Mature

Gibberellin A4/7 was applied to field-grown grafts of sexually mature poor and good flowering clones of Pinuscaribaea Morelet var. hondurensis. Barr. & Golf. Continuous applications of gibberellin A4/7 over a 6-week period significantly enhanced seed-cone production in poor flowering clones but had no effect on good flowering clones. Poor flowering clones also showed slight decreases in pollen-cone production with gibberellin A4/7, while clones that normally flowered well did not. Gibberellin A4/7 increased final shoot lengths in the lower (male) and upper (female) crown region of both poor and good flowering clones. A series of timed gibberellin A4/7 applications suggested that a single treatment near the onset of reproductive bud development may be used to enhance seed-cone production.

Some Factors Influencing Cone Production on Young Black Spruce in New Brunswick

1981 ◽  
Vol 57 (6) ◽  
pp. 267-269 ◽  
Author(s):  
J. D. Simpson ◽  
G. R. Powell
Keyword(s):  
New Brunswick ◽  
Picea Mariana ◽  
Black Spruce ◽  
Tree Height ◽  
Tree Age ◽  
Cone Production ◽  
Factors Influencing ◽  
Seed Cone ◽  
Pollen Cone

Ten young black spruce (Picea mariana [Mill.] B.S.P.) plantations in northern and central New Brunswick were examined to de termine the influence of aspect, slope, tree age and tree height on pollen-cone and seed-cone production. It was found that a greater proportion of trees growing on southerly aspects produced pollen cones and seed cones than trees growing on northerly aspects. Trees growing on southerly aspects bore 2.5 and 5 times more seed cones and pollen cones, respectively, than trees growing on northerly aspects. Cone production on south-sloping sites was approximately double that on level sites. The number of seed cones was most significantly correlated with tree height. The number of pollen cones was most significantly correlated with number of seed cones.

Promotion of flowering in white spruce (Piceaglauca) by gibberellin A4/7, auxin (naphthaleneacetic acid), and the adjunct cultural treatments of girdling and Ca(NO3)2 fertilization

1986 ◽  
Vol 16 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Richard P. Pharis ◽  
Debra Tomchuk ◽  
Frederick D. Beall ◽  
R. Marie Rauter ◽  
Gyula Kiss
Keyword(s):  
Fold Increase ◽  
White Spruce ◽  
Naphthaleneacetic Acid ◽  
Female Cone ◽  
Cone Production ◽  
Seed Cone ◽  
Sporadic Flowering ◽  
Old Trees ◽  
Pollen Cone ◽  
Temperature Water

Flowering (production of seed cone buds) of white spruce (Piceaglauca (Moench) Voss) grafts and of 55-year-old trees was significantly promoted by the application of gibberellin A4/7 (GA4/7). Use of GA4/7 accompanied by the adjunct cultural treatment of nondestructive girdling was especially effective. When GA4/7 was injected into a branch, the flowering stimulus was translocated upwards, thereby yielding up to a fivefold increase (72 female cone buds per propagule) in flowering. Clonal propagules sprayed to drip off with GA4/7 + auxin (naphtaleneacetic acid) averaged 116 female cone buds per propagule (a 12-fold increase over controls) with a 100% frequency of flowering. Pollen cone bud production and number of male flowering plants also tended to increase with the most successful flowering treatments. When GA4/7 was applied to 55-year-old trees with nondestructive, overlapping stem girdles and auxin, treatments were significantly effective (6- to 27-fold increases, respectively). When GA4/7 + Ca(NO3)2 was applied to 55-year-old trees, there was a tendency (nonsignificant) to increase (4- to 16-fold) flowering, relative to GA4/7 alone. White spruce, because of its very sporadic flowering and usually nominal response to GA4/7 alone, should be classed as a "recalcitrant conifer species." Use of the GA4/7 plus appropriate adjunct cultural treatments (high temperature, water stress, girdling) and (or) auxin is, thus, recommended if significant flowering and seed cone production is desired.

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